1. Technical Field
The present invention relates to a wavelength variable interference filter, an electronic device, a method of designing a wavelength variable interference filter, and a method of manufacturing a wavelength variable interference filter, etc.
2. Related Art
A Fabry-Perot etalon interference filter that includes a pair of reflection films facing each other (hereinafter simply referred to as “interference filter”) is known (for example, refer to JP-A-2012-042784). In the interference filter disclosed in JP-A-2012-042784, it is made easier to design the spectral characteristics of the interference filter by making the reflection characteristics of a first optical film, which is one of a pair of reflection films, and the reflection characteristics of a second optical film, which is the other of the pair, asymmetrical to each other. Specifically, each of these optical films is designed such that the center wavelength λ3 of transmitted light that passes through the interference filter will be within a range between the peak center wavelength λ4 in the reflection characteristics of the first optical film (hereinafter simply referred to as reflection center wavelength) and the reflection center wavelength λ5 of the second optical film (λ4<λ3<λ5).
A wavelength variable interference filter that is capable of changing the wavelengths of light outputted (transmitted or reflected) by changing the dimension of a gap between a pair of reflection films is known as such an interference filter. In such a wavelength variable interference filter, in order to output light that has desired wavelengths, it is necessary to control the dimension of the gap between the pair of reflection films with high precision. However, for example, when feedback control is performed on the dimension of the gap between the reflection films, the greater the dimension of the gap between the reflection films, the greater the variations in the gap dimension (poorer driving reproducibility). In the interference filter disclosed in JP-A-2012-042784 mentioned above, in order to make it easier to design the spectral characteristics of the interference filter, the reflection center wavelength of each of the optical films (reflection films) is designed. However, driving reproducibility based on the gap dimension is not considered. For this reason, even if the interference filter disclosed in JPA-2012-042784 is applied to a wavelength variable interference filter, it is not possible to improve driving reproducibility.